The present invention relates to an improved filtering apparatus for processing liquids.
FIG. 1 is a schematic sectional view of the configuration of a conventional filtering apparatus for processing liquids, in which a processing liquid tank 10 is divided into a contaminated liquid tank 14 and a clean liquid tank 16 by a partition plate 12 so that mixing is prevented. The contaminated liquid 18 stored in the contaminated liquid tank 14 is, for example, a processing liquid containing processing powder. In the clean liquid tank 16 is stored a clean liquid 20 which is resulted from filtering of the contaminated liquid. A pump 22 corresponding to a drawing-up means is provided in the processing liquid tank 10, the suction port side 22a thereof being immersed in the contaminated liquid 18. A filter 24 corresponding to a filtering means is provided in the clean liquid tank 16 by means of a filter fixing means 25 and is detachably fixed in such a manner that the filter 24 is immersed into the clean liquid 20. As shown in FIG. 2, the filter-fixing means 25 comprises a pipe-shaped mounting rod 27 with a hollow 26 and a mounting nut 28. The pump 22 and the filter-fixing means 25 are connected by a hose 29. A feed pump 30 serves to supply the clean liquid 20 which is resulted from filtering by the filter 24 to the body of a processing apparatus (not shown).
A description will now be given of the operation of the conventional filtering apparatus for processing liquids.
The contaminated liquid 18 which contains processing powder and which is returned from the body of the processing apparatus is stored in the contaminated liquid tank 14. The pump 22 which is constantly operated sends the contaminated liquid 18 stored to the filter-fixing means 25 through the hose 29. The contaminated liquid 18 sent to the filter-fixing means 25 is discharged in the filter 24 from the hollow 26 provided in the mounting rod 27. The contaminated liquid 18 is then filtered by the filter 24 with the aid of the pressure of the pump 22. As a result, the processing powder remains in the filter 24, and the processing liquid becomes the clean liquid 20 and is stored in the clean liquid tank 16. The clean liquid 20 is again supplied to the body of the processing apparatus (not shown) by means of the feed pump 30.
In the conventional filtering apparatus for processing liquids configured as described above, the filter 24 must be extracted from the mounting means 25 provided in the clean liquid tank 16 during the work of changing the clogged filter 24. During this work, the processing powder remaining in the filter 24 falls down into the clean liquid tank 16 and thus causes the contamination of the clean liquid 20. In addition, since the filter 24 constantly contains a processing liquid, the weight of the filter 24 is increased, and the filter 24 cannot be easily extracted. This causes the deterioration in the efficiency of the changing work and the difficulty in maintenance of the filter 24. There is also a problem in that a space for maintenance must be kept around the filter 24 for processing liquids.